SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48e52d31ad13ca649f6aa17d1846235d52c67e6fe983b69f5435e2472097d6eb' 
  AND token = '3n5a4TfI9XFIjHEr9+PXpqO5JjbB0QNlLOYNUp0jgGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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