SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7cb8774466e16c34f6020979012252496856f5a688b7db931f35c0aa12bda84' 
  AND token = 'PWF2FliyVtY9NoIuQwxiX+BWoeye7KJX8IHhNqpFjDc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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