SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63dd25b31dc3d95694b7dca34f5a9871a6610bd1413175adc5b070a329f66007' 
  AND token = '4KqJoufKog9fW/oJWpzOVzqyyDJh/NAFUrieLO7tRt0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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