SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3151a4f485bf82fc9dbf742cd9b832103dbf5920a73df20167fc5b66bcff5e72' 
  AND token = '6uLXPJWVvQqZMsTIB9bQ3yPT4JUhPXifLStnbIbwJVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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