SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3b99aef98fc37bb661dde0eb90e218749bf26397a919e94e6165f73835eca13' 
  AND token = 'UjzYrYdSDqJ01RHT0zD9aRz8IZaQD4t7EL5dpxEZl38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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