SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5a672af4741fa262823267b3053cf24317a2ead74f5747410d969857f338585' 
  AND token = 'qTvLl+abQWdT9N+XQWAHvD6GiYmxfKaLroWTCqhbG/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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