SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28cec5aec4d1876e84ae72aaecc9cb6ebdeb6575df590bf46539b6442dba0249' 
  AND token = 'JDQwussAgOnc094uyInq0LlhTYxjv3Drc3Fuqot3RMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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