SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b345b6950188651a74b558f8af23daf4e07d406784fb41b9ff3d1c1d8965cf7' 
  AND token = '3JOqLz6CiBbej332VJxhGZ4R6VCzKOIgXeSfJ7kXvvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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