SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7be69521ce986d649215338b69e239408b4c9efe8aa30177a94346c25b9be078' 
  AND token = 'EqJJQko13avWwyCFUwpoKg8DaYO19IiXS5B9gmPW8tI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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