SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e999b5a294670e20fb80ab1ece51a88d3985c663534acbe2323300b8ec74996' 
  AND token = '817bKVulxExjnUKesObGKn5+vFcqGT3I0zFpIy60bBU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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