SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aef9647163ced70f0ce6fee4b1d5fb39e820290400c141a9ae5f319e6889b51a' 
  AND token = 'pQ2E8kgWgGvDjPrThiOmjH852rApEGty65EzuSlNyXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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