SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '379abd551b46ffe0164870fae9ee1fb66d3f56928489cf93b6791588b876809b' 
  AND token = 'fufpatwRMbWmmaUvBbLVfYLKEN7HihepgmSnKiQB158=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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