SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '274ce1a74c699bc3fb881901aa8cd9f691f1f7f1fb1c19cb5331fda6dde12a3f' 
  AND token = 'H/cYNR7VunnXCcsbtO80RNFFjK5VzNwvOXYfQOvXXpo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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