SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7e4199cb4e6cb5674630aa8e61bae0a095523974f0548382decd952fb7cf039' 
  AND token = 'Sl5rUnr/9d29K4vyEvWIvxXNeYAyBfZxjt6AnQ5ICFs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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