SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20bd1cb58707567b516555ff9da6f66b36a3674fdfca9e3fb1a1e0910e6ddde2' 
  AND token = 'YsPHKSWyr2hOHMqdzjfJcHmjDhHinYnB5pCQAoC1JSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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