SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb1276de519c45fe486dead1b8dca8e794a8db1c93b51622500c2a6e65869181' 
  AND token = 'XAuek9CHYpVqAcqBbfXi3JUnI2DpstcA4GZhEhHD/YY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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