SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3d91c0adf5cfc5af58659ea177fb41268cf1ca3ed97b1a9b5ea3b1f2308bef6' 
  AND token = 'SGZUxXtGQJmBSchPrBCPmTKgIJtl/LB49qrpZDtS69g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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