SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a198cc576f21d4cd73e68bf178b32f6c174c0e13b7065874a7e23f5ebba9a986' 
  AND token = 'dw8QMuJLUUeZ6VTpUwSK0GK0JCQqdLSygYxUsPp+wF4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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