SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db5fd0f46d5b7ec97758d7405ccc95acdbad69467000bbfe87af8f3f22bb62f2' 
  AND token = 'LXmgo4RQzIEoT00SUNxk5jmaA90osBYDqUF1rH4THAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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