SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7dec3f7c759751745073d017ee4b009704cb3334e86880c1240f62d90a62733' 
  AND token = 'xhSX+gkobgDgmzvAFZ6ffU/wBbLm1mBfu1XxH5ansD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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