SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b318d22089554c7aadd7ca8b2554a9a438704c7f2dbf0ebb86c7784d04916a6d' 
  AND token = 'zsvTq12AdTIOPqmwwm/geYw6+98rvLM1dyK4vJKiIc0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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