SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7ac8c7c5fbf10da29554993bc1e08611437cdace53f64eb2b45a6bc998f35ae' 
  AND token = '6lp4buvMV5JhxhrxfAZmlrsh46FcbA+EHdvvmhVgYuk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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