SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '135f6369cd664481d92835119bc68454e7b7163d21ab2b5f99dc78aa403d2da2' 
  AND token = 'JATMGBBvvqPMXRQuA4l8+zs8E7+awJLoXk/tBKEDlhg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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