SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '854b38b3060d0ccfce491a54f75f0cf49c1951a6ca8e9264719b6008e081a1e1' 
  AND token = 'RfvcjyZVm1Apm2Dpjg8/b1cfD1DfzqNp0OdgUqU34ow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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