SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd94c640be00bc63ce346c8b29dd269deffc3dacff8ac2660adb7f9a08b722ade' 
  AND token = 'Y6aU6Ak7fDnWIfafbUKWm06mzhJF7wB0gN+dsh9Li7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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