SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6aa119924199f262f4de44a9c2a68581b36106aa0da917959da3372bfd1d8e97' 
  AND token = 'TxVPwNWpm3LlHohsD+eG1cCL/g0KLYiVviTIXjDZiVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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