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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '210ce41284b1c6638ce4280409f093a0537c8c3c0ede0607f0e78c4efa5ee643' 
  AND token = 'c4yvnCdnsqQkF7qN2NBKacHrrXHiGEARsZlvWqEG/kY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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