SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1379789e53425412965acb25c1b18d702db992101281134a463a8b00b49ab4a' 
  AND token = 'kYwj/qckhsUxExf+QKy8qPwCRm+v4MnLcqdabXHGCAA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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