SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a5d66b447a09f48438ca32a42eca76659beccc75288d7ddcfacf18442d69d0d' 
  AND token = '4nZp1yz5CTtuUPQv3VKHFv8JRVh5zVVasGFVfzoWLNg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}