SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7099ccc88715e5048ebdde36a6af4c3b8a97318fe042b3575bbc085b08e5f88' 
  AND token = 'VGtnelzw4VrayqltZ4rBF0BA2+or77Pp/ChI+YwDjAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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