SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03bec037ea9f660fb490fc2241373c5211e687619b0e83edeeb81736b675b144' 
  AND token = 'eUeRZ2+/rBt1HieOGLt67bX/6yz7jpGXvxBqhw7Dij4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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