SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bfade14073f6f2b0475d4dc741cf1bea575f3a65fa80658fa924d1f735dc7fd' 
  AND token = 'JXmYKJCtfafTzS3IbKkfzYwlmDsXJj+asD/zDlFGBbg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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