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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '302ae1fc37015dd5e079334c6bce7dbea9cddd6b4fff8dd981a146f5f5c7bc20' 
  AND token = '9yVY3U1ogGKjkrps1KxxlYybRTgAXqLcezObLz64+dQ=' 
  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"
    }
  }
}