SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4858d9130e0fb12696027873ac7e7958455a2f48f4588626acd566b6854f306d' 
  AND token = 'IU5TEgIKpCMj1dVh/FWSjXImS3+nzkJxcbVlvfM8v1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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