SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be1ba4d670c3ce88093c7eaddb13e0f960a84f81fc6d54939eced727892ad563' 
  AND token = 'VUOBo/vTxPGS5Zngbg96P6ypXWd4uzxPrQtwf+FlLK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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