SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1943b41673d28211825572806e55b58e519f754d13db0ae7eb45458ba4690d09' 
  AND token = 'QE2WlvxpUuV/RdZQ7FijGOrlLQRFuSBGXFlpkwKwcD4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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