SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ebca5612246497b5455434c9e6e091bb3cf688f393d0f879e951ce084bcf141' 
  AND token = 'qwmkJnxFbuY8v+zgcQeXu+s7/DuYq7Geip6HPsuFesg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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