SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52498e91dba70b087ada96ef0e6b9ad4e7b6dbf542ed90e2603f05a629818ad8' 
  AND token = 'iHJe+664G/Pq1fYNJhLmCtuVyN51TTW6xhHSyPWRzpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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