SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78f2976dc1457f66caf859eda551dd1fc25b3a32a7c06b71aa04f6943cbf3c6d' 
  AND token = 'heLjiUU70Vn0DeacXNa/lanq5RRwQBumXKdpWMqyZs0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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