SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9ada094bda9efa5f0b7f202b8f20aea4662c45ea460134711204ce70f34b518' 
  AND token = 'nPU1y2ekNlLLqP21dBpWlD4VVz7F0G7luFv1+LSXm0I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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