SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9341b82275d52d1f28e3e21ac3db5049fa59b321f1a63209910148dc1a31f54' 
  AND token = 'RCwAauoN4vw2RRnw+IAKcoGBpqaS4OlKo27PgUiuZ7M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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