SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '910750b00b74773f62d4a3540b89337f5e64d9a1af250eeff8f108b672b3115f' 
  AND token = 't/yzOjCImUDX2UlGlOztL15z4yGQ8mpaSXgpPIelaVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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