SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3fc2dc90b657543446a2b927119d5c18f98827bccce232bc4b5e9429a4a0d18' 
  AND token = 'tYvfQK7Lt6RSxsMt8/gr9qnOnRTKYQJTJhcWxjezaBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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