SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3449fec64dd0ad32c6658a37ad7fae921c023815ee7b4d56a79d4915916db9d0' 
  AND token = 'iFbhudhj2JVj7+GEUlFviQ3ksAq/9cMXI2LEHN+y6V0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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