SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8fac38a63774ee749b8bcda8348772017c3d0a87f5bed5923b2bcc596f52f24' 
  AND token = 'Phj44tc+HjfK5YNrJOB8/SjJ6hV5MeTneorOqmwUAjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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