SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2ba0c02a76b1708591370f8ba39adfadf18ed98c3850f76f1ccdff884ac6c4f' 
  AND token = 'onOijcmsL6RUgjZUUCnswom3lJgw5/UPhQmsz3uB4zs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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