SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '477d871832a1215a84bcf5b1c048f186d355e02f5a5f54d62021c9bf9426c370' 
  AND token = 'JX5z2YJfI4FOK2LyQR5W21fdEWTjYzuzgd+aR+/7iyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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