SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b31b11da820aa710c25f10ca08c9e4c75a479c5e91a588b604578f28d716ec49' 
  AND token = 'AtQWd3n7WHvN+GP4TMCKpIag9IXRt2T3fcHJg0ALS5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}