SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'fe76c3c4cbbe261689ef4b653ccdcb3a4c740ecef6c9ad3a788c7ae4ffa7854d' 
  AND token = 'puCm7zrIwD4gTlHPTaaYtO+YC6FwWUw0LDOGBourYEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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