SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92934606782bb31ffbf3307557f079b802b352641544196a3d55a08f5a57fbd3' 
  AND token = 'QZV8vY9+gRysXZ8Fg0BFQ6caHc5KKePPFQL92tWX7es=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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