SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9875884c1b182934a00a6a0ec7ab4c74f7cbb33d92a8d4534bc0a74c496a8af6' 
  AND token = 'ZKWxtGZMpSEKMh1NUmoEQd9zjXlp5hRyFWvq5OfoEyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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