SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70a0af9549303b46d424873daec00461df296bedc016b6bc412411a218c435bd' 
  AND token = 'dgwZFV6lGnJI8RsyQqMGRMuZUDDdybRDL2Y5W7alScs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00063

JSON explain

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