SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '717ca22859bd5188413f12d3879abcbd028d03252caacbc114136ecd8ebb2e0a' 
  AND token = 'E9kzwHFz7lPpJqIIeobVrU8G1LrmPguZBQ2IzmPyvek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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