SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b00b8af1154b454544dec2a3fe58da8d823efaacf17e1825f35b1606eb824a9' 
  AND token = 'ErRp7qtNAppGF35L+1palTYMGfSLIhHOh6jaWJhWmTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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