SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76a5d410e1d44ac329b9ff0085c31d858978809f729528f7a8bbe2c201a61fb1' 
  AND token = 'ZQGLRRSoYkoR/6kd1Zdx2M45gZmJGtyUrbPBV14s58Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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