SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0cf809475839bac9cdcf74df98e03fa7c882a954deb069e57d1946d5c19a3e8' 
  AND token = '2dWY/UGw75rgjRueLBNhIB+qGptyFqR4pfEmtNe2Trw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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