SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1605f709039812a13758b65cf5d65b7efb5f231e6349ecc5f41e3c7e8e381420' 
  AND token = 'OidjAWPl7nNiHsWHpCMKkMFfM+j/B9MmksJbYc0rGEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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