SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31a61cfe954778fc7813a4afe0e691e82783634022fe29146c933afce69dbed6' 
  AND token = '5NET/Jt8Vn3AJ0dBx6BpXiCIRiyYrSphsbZ3ZUtGx6E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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