SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd85164d7c81463ebf57354e2048682912171a80c6d9d9b7ac2f1120f0f198bdf' 
  AND token = 'tkqbctVJwPsgjaEKAAV+2EDSstLgtzhHTElU84HhuGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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