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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f9c63216e9565107ad63bb7fea1c724addb68a0305ebb6036616aab3da4c60e' 
  AND token = 'MLmU5Cxdi3Nv+flHnBswsmDxUMMJ8ah1QGv2HtnUTR4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}