SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a13be266014a482b97556f68c4ebde2bd0c1e704479ecf362aff7f5e9adf532b' 
  AND token = 'aaIRDLR4+rdiTN3erP224zNgnn9+RUmy79pZhuXj4gw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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