SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbfd61eb9b64fef2477e01a1723fc83894ba7769f764eb0907b317a2a8443ee8' 
  AND token = 'W0ojoyVHcFddoKzJhywx5ctyLcN9zD7SlMeZVV6cScg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}