SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfcb872362814e58f212e7a85beec0c18558e84e0535767ba3054a06a553bff1' 
  AND token = 'BjaFzC9HhVpw7YVxj6GzS+FlP0TiyXtlh9/C/Hn+hgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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