SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13b40a0daba2ae68d0e5c9b04f87e66e15b69e85965cbecd85b549aba2a61083' 
  AND token = 'oWmtWPXk6kbDlFHm7n4KqrqGhty5kbZOKdH+hLztmgI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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