SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74ff3968d4f51ed0a11f29a1bc7225f5fed0446eb626da0704c16aad36b005a7' 
  AND token = 'Cs90bD0q8XQAmT+Y8DeLdPCsCv9mcgev+mVeAzQeL/o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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