SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fa076f7a8281c6c4dce8597575f05cb931e10cb0a5bf8203b06daafed3fca4d' 
  AND token = '54UTv8dWILXTTersSytI0Rlt5QDNtHYMsZCvveNfgk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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