SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a1b56c0aa6ac75c5267695af10a1f88d24318173220848d3278376584a2bb4f' 
  AND token = 'Wax6873/UCpaeToAWl6wztvi2wRYTbAbzWUuAZj/5wE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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