SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d2c14eab280793fdb03842eb72336c68f8d770af4779824e3706f288ea99a02' 
  AND token = 'kXFZuU/KhTXUNb+iupdLwT5xh+MuJ6fVnB5Qv4GPPsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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