SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '637ceab1bcc113222f3aeabe4335ef01f24692a6218e39d4a97236a56aa1b277' 
  AND token = 'lHnxWEivNWUGp2hXEyuS/KAcuVidAcNGkwlbO2moW0A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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